Long-term goals are: to understand effects of ultrafine (less than 0.lMum) combustion aerosols and their reaction products with S02 on the lung, to characterize them and to understand processes leading to their formation during coal combustion. All aerosols are made in furnaces usable as feed-systems for animal exposure chambers. Exposures include: ZnO alone and with SO2, CuO alone and with SO2, coal combustion products generated from burning of characterized coals under controlled combustion conditions, and ultrafine aerosols of silica having a surface layer of ZnO alone and with SO2. Guinea pigs are exposed for 1 hr, 3 hr, 3 hr/day for 6 days, or 3 hr/day, 5 days/wk for 3 wks. Effects are evaluated at 1, 24, 48, 72 hrs post-exposure and, for the chronic studies, on alternate days up to 10 days after exposure. Functional change during exposure is evaluated by measurement of respiratory mechanics. Pulmonary function following exposure is evaluated by measurement of lung volumes, CO diffusing capacity, expiratory flow rates and N2 washout. Pathologic changes are evaluated by light and electron microscopy, uptake of 3H-thymidine by epithelial cells of the bronchiolar and alveolar regions, permeability of respiratory epithelium to horseradish peroxidase, increase in plasma angiotensin converting enzyme and examination of lung lavage fluid for cell population and content of lytic enzymes. Biochemical and pharmacological mechanisms underlying the changes will be examined. These studies include: balance of various prostaglandins, effect of cholinergic and adrenergic blocking agents and blockage of mast cells. Characterized coals are burned in a laminar-flow furnace which permits control of temperatures and oxygen partial pressure; the effect of coal composition and combustion conditions on the formation of ultrafine aerosols and of H2SO4 are determined. This information is needed for design of control strategies. Because ultrafine aerosols and SO2 are emitted to the atmosphere together by coal combustion and by smelting of ores, information on formation, interaction and toxicological effects is needed to understand potential health effects.